Intuitive ultrasonic imaging system and related method thereof

ABSTRACT

A hand held ultrasonic instrument ( 10 ) is provided in a portable unit that performs C-Mode imaging and collects 3D image data. In a preferred embodiment a transducer array ( 60 ), display unit ( 20 ), beamformer ( 40 ), power system, and image processor are integrated in one enclosure weighing less than three pounds. In operation, the portable unit is scanned across a target and the displayed image is conveniently presented to the operator whereby the displayed image corresponds exactly to the target, or a scaled fashion if desired.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/762,135 filed on Apr. 16, 2010, which is a continuation of U.S.patent application Ser. No. 10/506,722 filed on Sep. 7, 2004, and issuedas U.S. Pat. No. 7,699,776 on Apr. 20, 2010, which is a National StageFiling under 35 U.S.C. 371 of International Patent Application SerialNo. PCT/US2003/006607 filed on Mar. 6, 2003, which claims the benefit ofpriority to U.S. Provisional Patent Application Ser. No. 60/362,763filed on Mar. 8, 2002, the benefit of priority of each of which isclaimed hereby, and each of which are incorporated by reference hereinin its entirety.

FIELD OF THE INVENTION

The present invention is directed to ultrasonic diagnostic systems andmethods and, in particular, a substantially integrated hand heldultrasonic diagnostic instrument.

BACKGROUND OF THE INVENTION

Medical imaging is a field dominated by high cost systems that are socomplex as to require specialized technicians for operation and theservices of experienced medical doctors and nurses for imageinterpretation. Medical ultrasound, which is a considered a low costmodality, utilizes imaging systems costing as much as $250K. Thesesystems are operated by technicians with two years of training orspecialized physicians. This high-tech, high-cost approach works verywell for critical diagnostic procedures. However it makes ultrasoundimpractical for many of the routine tasks for which it would beclinically useful.

A number of companies have attempted to develop low cost, easy to usesystems for more routine use. The most notable effort is that bySonosite. Their system produces very high quality images at a systemcost of approximately $20,000. While far less expensive than high-endsystems, these systems are still very sophisticated and require awell-trained operator. Furthermore, at this price few new applicationsare opened.

The applicability of conventional ultrasound is further limited by thetypical image format used. Images are produced in what is commonlyreferred to as a B-Mode format, representing a tomographic slice throughthe body perpendicular to the skin surface. This image format isnon-intuitive and the simple act or process of mentally registering theB-Mode image to the patient's anatomy requires significant experience.

Most existing ultrasonic imaging systems utilize an array transducerthat is connected to beamformer circuitry through a cable, and a displaythat is usually connected directly to or integrated with the beamformer.This approach is attractive because it allows the beamformer electronicsto be as large as is needed to produce an economical system. Inaddition, the display may be of a very high quality. Unfortunately thisconfiguration is not intuitive for most users because the image appearsfar from the patient. Furthermore, these systems typically acquireB-mode images, that is, images consisting of a tomographic slice takenperpendicular to the face of the transducer array. Most new users findimages in this format very difficult to interpret and to registermentally with the tissue geometry. Conventional system configurationscan be awkward to use because of the lengthy cable involved. Finally,the typical large size of the beamformer limits the system'sportability.

Some conventional system architectures have been improved upon throughreductions in beamformer size. One of the most notable efforts has beenundertaken by Advanced Technologies Laboratories and then continued by aspin-off company, Sonosite. U.S. Pat. No. 6,135,961 to Pflugrath et al.,entitled “Ultrasonic Signal Processor for a Hand Held UltrasonicDiagnostic Instrument,” hereby incorporated by reference herein in itsentirety, describes some of the signal processing employed to produce ahighly portable ultrasonic imaging system. The Pflugrath '961 patentmakes reference to an earlier patent, U.S. Pat. No. 5,817,024 to Ogle etal., entitled, “Hand Held Ultrasonic Diagnostic Instrument with DigitalBeamformer,” hereby incorporated by reference herein in its entirety.While the titles of these patents refer to a hand-held ultrasoundsystem, neither integrates the display and transducer unit. In U.S. Pat.No. 6,203,498 to Bunce et al., entitled “Ultrasonic Imaging Device withIntegral Display,” hereby incorporated by reference herein in itsentirety, however, the transducer, beamformer, and display are allintegrated to produce a very small and convenient imaging system. TheBunce '498 system, however, has some imitations. For example, but notlimited thereto, Bunce '498 continues to use the confusing b-mode imageformat and its configuration is not intuitive for some users making itdifficult for an untrained user to interpret the image and connect it tothe organ, target, or subject under investigation.

The present invention ultrasonic imaging system and method provides theopportunity to be a common component of nearly every medical examinationand procedure. The present invention provides a system and method whichshall be referred to as “sonic window”.

The present invention system may be produced, and the related methodperformed, at a low cost and will be nearly as easy to use as amagnifying glass.

The present invention ultrasonic imaging system and method provides thepotential to have a broad and significant impact in healthcare. Theinstant document identifies various clinical applications of the presentinvention sonic window, but should not be limited thereto, and otherapplications will become attained as clinicians gain access to thesystem and method.

SUMMARY OF INVENTION

The present invention comprises a hand held ultrasonic instrument thatis provided in a portable unit which performs C-Mode imaging andcollects 3D image data. In a preferred embodiment a transducer array,display unit, beamformer, power system, and image processor areintegrated in one enclosure weighing less than three pounds. Inoperation, the portable unit is scanned across a target and thedisplayed image is conveniently presented to the operator whereby thedimension of the displayed image corresponds exactly to the dimension ofthe target. Alternatively, the displayed image is a scaled version ofthe target. If scaled, then the image may be magnified or reducedaccordingly.

In one aspect, the present invention provides an ultrasonic imagingsystem capable of producing C-Mode images and/or collecting 3D imagedata of a target. The system comprising: a housing; a transducer arraydisposed on the housing; a display unit disposed on the housing, whereinthe transducer array and the display unit are integrated with thehousing; and a beamformer is in communication with the system.Alternatively, the beamformer may be integrated within the housing.

In another aspect, the present invention provides a method of imaging atarget to produce C-Mode ultrasonic images and/or collect ultrasonic 3Dimage data. The method comprising the steps of providing a housing;providing a transducer array disposed on the housing, the transducer fortransmitting ultrasonic energy into the target and receiving ultrasonicecho signals from the target; beamforming the received echo signals toprovide data; processing the beamformed data; and providing a displayunit disposed on the housing, the display unit displaying the processeddata.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of the presentinvention, as well as the invention itself, will be more fullyunderstood from the following description of preferred embodiments, whenread together with the accompanying drawings in which:

FIGS. 1A and 1B illustrate schematic representations of the presentinvention ultrasonic imaging system having an integrated beamformer anda stand alone beamformer, respectively.

FIGS. 2A-2B schematically illustrate top and bottom perspective views,respectively, of the hand held ultrasonic imaging system of the presentinvention.

FIGS. 3A-3C schematically illustrate various embodiments of the accessports, access outlets, and passages of the hand held ultrasonic imagingsystem of the present invention.

FIG. 4 schematically illustrates an adjustable display unit of the handheld ultrasonic imaging system of the present invention.

FIGS. 5A-5B schematically illustrate top and bottom perspective views,respectively, of the hand held ultrasonic imaging system of the presentinvention having a cover thereon, as well as adhesive devices on thehousing and/or cover.

FIG. 6 schematically illustrates a top perspective view of the hand heldultrasonic imaging system of the present invention having a retainingdevice thereon.

FIG. 7 illustrates in block diagram form the architecture of anembodiment of the ultrasonic imaging system of the present invention.

FIGS. 8A-8B, show a schematic longitudinal perspective view and lateralside view, respectively, of the hand held ultrasonic system wherein thecurve of the display, housing, and/or transducer is in the longitudinaldirection.

FIGS. 9A-9B, show a schematic longitudinal perspective view and lateralside view, respectively, of the hand held ultrasonic system wherein thecurve of the display, housing, and/or transducer is in the lateraldirection.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a new ultrasound system architecture andrelated method thereof that eliminates many of the problems andlimitations associated with conventional architectures. The presentinvention system and method, termed the sonic window, integrates thetransducer array and the display unit so that the ultrasound image isdisplayed at the location it is acquired. More significantly, the sonicwindow obtains C-Mode images, that is, images in which the image planeis parallel to the surface of the transducer.

Novice ultrasound users, among other types of users, would find thepresent invention system and method very useful and beneficial. C-Modeimage formats are discussed in U.S. Pat. No. 6,245,017 to Hashimoto etal., entitled “3D Ultrasonic Diagnostic Apparatus,” hereby incorporatedby reference herein in its entirety, as well numerous other patents. Thepresent invention sonic window may also acquire and display 3-D images(and/or transmit the images to exterior devices for display).

The C-Mode image of the present invention and method may be selectedfrom an arbitrary depth depending upon user preference and the specifictarget or tissue of interest. A preferred embodiment would include asimple user control, such as a thumbwheel, to select the depth of imageacquisition. Likewise, a preferred embodiment would also include asimple display indicating the depth selected.

As shown in FIG. 1A, the present invention imaging system utilizes atransducer array 60 that is in communication with beamformer circuitry40 and a display 20 in communication to the beamformer 40. Thetransducer 60, beamformer circuitry 40, and display 20, are integratedwhereby they are located in the same general housing (enclosure) or onsame general platform or board. Images are formed by transmitting aseries of acoustic pulses from the transducer array 60 and displayingthe magnitude of the echoes received from these pulses. The beamformer40 applies delays needed to steer and focus the acoustic pulses andechoes.

While full integration of the transducer, beamformer, and display ispreferred, it should be appreciated that in some instances only thetransducer and display are integrated, keeping a cable 50 to connect thetransducer unit 60 and display unit 20 to a separate beamformer unit 40,as show in FIG. 1B. Rather than a cable, a channel that carries signalsmay be implemented using wire or cable, fiber optics, a phone line, acellular phone link, an RF link, an infrared link, blue tooth and othercommunications channels.

The beamforming operations of the present invention system and methodmay be distributed between the transducer/display unit and a separatebeamforming unit. Such a design would be intermediate between the fullyintegrated approach and the separate beamformer approach describedabove. This approach has the advantage of limiting the amount of datawhich must be passed between the transducer/display unit and thebeamformer unit.

As the present invention system and method provides an integratedtransducer unit 60 and a C-Mode or 3-D display 20, a variety of tissueinformation may be obtained through judicious pulse transmission andsignal processing of received echoes. Such information could bedisplayed in conjunction with or instead of the aforementioned echoinformation. One such type of information is referred to as color flowDoppler as described in U.S. Pat. No. 4,573,477 to Namekawa et al.,entitled “Ultrasonic Diagnostic Apparatus,” hereby incorporated byreference herein in its entirety. Another useful type of information isharmonic image data as described in U.S. Pat. No. 6,251,074 to Averkiouet al., entitled “Ultrasonic Tissue Harmonic Imaging” and U.S. Pat. No.5,632,277 to Chapman et al., entitled “Ultrasound Imaging SystemEmploying Phase Inversion Subtraction to Enhance the Image,” both ofwhich are hereby incorporated by reference herein in their entirety. Yetanother type of information that may be obtained and displayed is knownas Power Doppler as described in U.S. Pat. No. 5,471,990 to Thirsk,entitled “Ultrasonic Doppler Power Measurement and Display System,”hereby incorporated by reference herein in its entirety. Angular scatterinformation might also be displayed. Such data could be acquired using amethod described in a co-pending U.S. patent application Ser. No.10/030,958, entitled “Angular Scatter Imaging System Using TranslatingApertures Algorithm and Method Thereof,” filed Jun. 3, 2002, of which ishereby incorporated by reference herein in its entirety.

Speckle is a common feature of ultrasound images. While it isfundamental to the imaging process, many users find its appearanceconfusing and it has been shown to limit target detectability. A varietyof so called compounding techniques have been described which could bevaluable for reducing the appearance of speckle in sonic window images.These techniques include spatial compounding and frequency compounding,both of which are well described in the literature.

The present invention acquisition of 3-D data sets also allows a newtype of compounding that might be termed “C-Mode compounding.” In thistechnique a number of envelope detected C-Mode images from adjacentplanes would be summed to yield a single speckle reduced image. Whilesome resolution in the slice thickness dimension would be lost by thisaveraging, the improvement in effective signal to noise ratio achievedby reducing the speckle might outweigh that cost.

One skilled in the art would appreciate that the common practice offrequency compounding could be readily applied to the current invention.By transmitting a plurality of pulses at different frequencies andforming separate detected images using the pulses one may obtainmultiple unique speckle patterns from the same target. These patternsmay then be averaged to reduce the overall appearance of speckle.

The well known techniques of spatial compounding may also be applied tothe current invention. The most conventional form of spatialcompounding, which we call two-way or transmit-receive spatialcompounding, entails the acquisition of multiple images with the activetransmit and receive apertures shifted spatially between imageacquisitions. This shifting operation causes the speckle patternsobtained to differ from one image to the next, enabling image averagingto reduce the speckle pattern. In another technique, which we termone-way or receive-only spatial compounding, the transmit aperture isheld constant between image acquisitions while the receive aperture isshifted between image acquisitions. As with two-way spatial compounding,this technique reduces the appearance of speckle in the final image.

In many ultrasound applications the received echoes from tissue havevery small amplitude, resulting in an image with poor signal to noiseratio. This problem may be addressed through the use of a techniqueknown as coded excitation. In this method the transmitted pulse is longin time and designed so that it has a very short autocorrelation length.In this manner the pulse is transmitted and received signals arecorrelated with the transmitted pulse to yield a resultant signal withgood signal to noise ratio, but high axial resolution (short correlationlength). This method could be readily applied in the present inventionsonic window device and method to improve the effective signal to noiseratio. The coded excitation technique is described in U.S. Pat. No.5,014,712 to O'Donnell, entitled “Coded Excitation for TransmissionDynamic Focusing of Vibratory Energy Beam,” hereby incorporated byreference herein in its entirety.

An aspect in fabricating a system like the present invention sonicwindow is in construction of the transducer array. Both cost andcomplexity could be reduced by incorporating a transducer fabricatedusing photolithographic techniques, i.e. the transducer is formed usingmicroelectromechanical systems (MEMS). One particularly attractiveapproach has been described in U.S. Pat. No. 6,262,946 to Khuri-Yakub etal., entitled “Capacitive Micromachined Ultrasonic Transducer Arrayswith Reduced Cross-Coupling,” hereby incorporated by reference herein inits entirety.

In an embodiment, the present invention ultrasound system and methodproves particularly valuable for guiding the insertion of needles andcatheters. Currently, technicians attempt to insert needles based on thesurface visibility of veins coupled with their knowledge of anatomy.This approach works quite well in thin, healthy individuals, but canprove extremely difficult in patients who are ill or obese. The lowcost, easy to use present invention imaging system and related methodprovides additional guidance in these cases, increasing the efficiencyof treatment, reducing patient discomfort, and improving patientoutcomes by speeding treatment. Such a low cost, easy to use systemwould undoubtedly find additional medical applications.

As shown in FIGS. 3A through 3C, the system 10 may have an access port65 that is configured to receive a medical instrument, medical tool,other instruments, other tools, other needles, probes, or the like. Inclinical use an instrument or needle could be inserted into the accessport entry 63, pass through the device through a passage 65, and enterthe tissue near the outlet 64. An instrument inserted through thepassage 65 will intersect with the image plane 3 at the intersectionpoint 4. The displayed image could readily indicate the location wherean inserted needle or the like would enter the tissue or other target.The displayed image could show where the needle, instrument, and/or toolwould intersect with the image, even if it doesn't actually show theneedle, instrument, and/or tool. Likewise, the image could have anintersection point indicator 21 to show or indicate the location of theintersection point 4 within a given image. The location of the accessport 63 is not limited to the upper surface of the device, but couldalso be located on any of the device sides 12, 13, 14, 15. A device mayinclude multiple access ports 63 to enable access from differentlocations or simultaneous use of multiple tools. A system with multipleaccess ports 63 might include internal sensors (not shown) to determinewhich ports were in use at a given time and thereby provide appropriateindicators on the display. The outlet(s) 64 or access port entry(entries) 63 might be located within the transducer array 60 or at alocation outside or adjacent to the transducer array 60, for example onthe sides 12, 13, 14, 15, top 6 or bottom 8 of the housing 2, or otheravailable components of the system 10.

It should be recognized that the access port 63, access outlet 64, andpassage 65 may in combination in whole or in part include, but notlimited thereto, the following: recess, aperture, port, duct, conduit,channel, pipe, tube, hose, tunnel, channel, flute, fiber optic, orequivalent structure.

For example, but not intended to be limiting, FIG. 3A schematicallyshows the passage 65 running from the top 6 to the bottom 8. Next, forexample, but not intended to be limiting, FIG. 3B schematically showsthe passage 65 running from the top 6 through transducer array 60. Stillfurther, for example, but not intended to be limiting, FIG. 3Cschematically shows the passage 65 running from one of the sides 13 (oroptionally from another side 12, 14,15) to the bottom 8 (or optionallycould have been through the transducer array 60 as well).

Also shown in FIG. 2B, the system may also have a transducer 60 orhousing 2 incorporating a marking devices or mechanisms 67 wherein whenthe devices or mechanisms 67 come in contact or near contact with thetarget 1 (e.g., skin or surface), or when the user so instructs thesystem, then the marking devices or mechanisms 67 place or apply one ormore marks on the target 1. Such marks may include raised bumps,indentations, dye, or other suitable means. Marks formed in this mannermay be useful for guiding surgical or other interventions which willoccur without the sonic window device in place. Additionally, the marksmight provide useful for maintaining device registration while surgicalor other medical procedures are performed with the sonic window inplace. Likewise permanent or semi-permanent marks might be used to guidethe sonic window to the same location during later imaging sessions.Such alignment would be facilitated by the inclusion of optical or othersensing devices (not shown) on the face of the sonic window containingthe transducer array.

Still referring to FIGS. 2A-2B and 3A-3C, an embodiment of the hand heldimaging system 10 is described. The system 10 comprises a housing 2 (orplatform, board, enclosure, casing or the alike) preferably formed ofplastic or metal or other desirable materials appreciated by thoseskilled in the art. The enclosure has four sides 12, 13, 14, 15 (but maybe more or less according as desired), a top side 6, and a bottom side8. The display unit 20 is on the top side 6 and transducer array 60 ison the bottom side 8, substantially or exactly parallel with the display20. The system 10 may also have various controls for the user, forexample, roller ball or toggle stick 19, alphanumeric keyboard 18, andor menu buttons 7.

As best shown in FIG. 2B, the system 10 also has a communicationinterface 87 that is operable with a communication path or channel 88(shown in FIG. 7). The communications interface 87, for example, allowssoftware and data to be transferred between the system 10 and externaldevices. Examples of communications interface 87 may include a modem, anetwork interface (such as an Ethernet card), a communications port, aPCMCIA slot and card, etc. Software and data transferred viacommunications interface 87 are in the form of signals which may beelectronic, electromagnetic, optical, or other signals capable of beingreceived by communications interface 87. Signals are provided tocommunications interface 87 via a communications path (i.e., channel) 88(as shown in FIG. 7). The Channel 88 carries signals and may beimplemented using wire or cable, fiber optics, a phone line, a cellularphone link, an RF link, infrared link, blue tooth, and othercommunications channels. It should be noted that in general othertransmission channels associated with the system may utilize similararchitecture.

As best shown in FIG. 2A and FIG. 4, the system 10 may have a displayunit 20 that may be adjustable relative to the housing 2 or othersuitable structure of the system 10. In one preferred embodiment,adjustment of the angle of the display 20 would alter the angle of animage slice selected from a 3D volume of space. The user would thus beable to select the image plane of most interest by simply adjusting thedisplay angle (e.g., from about zero to about 135 degrees), as depictedby arrow A, until that slice was displayed. This approach should providea useful mode of navigation for novice users. FIG. 2A illustrates thedisplay 20 in a position substantially or exactly parallel with thetransducer array 60. FIG. 4 illustrates the display 20 that may berotated in any desired angle relative to the transducer array 60. Theadjustment device 22 or devices may be a variety of devices orcombinations thereof including, but not limited thereto, the following:gimbal, spindle, core, axle, shaft, rod, arbor, mandrel, axis, pin,pintle, bar, journal, and bearing.

FIGS. 5A-5B schematically illustrate top and bottom perspective views,respectively, of the hand held ultrasonic imaging system of the presentinvention. In particular, a cover 31 or covers (removable,semi-permanent, or permanent) are provided on the bottom 8, for example,or at least a portion of the bottom 8, that is/are applied to achieve aclean, sterile, or antiseptic condition. The cover 31 would be theportion of the device in contact with the patient or target. Optionally,the cover 31 could be disposed on other areas of the housing 2 or system10. In addition, the cover 31 may require intakes 34 or via for objectsto pass through the cover 31 to the marking mechanisms 67 and/or accessoutlets 64. It could include portions meant to extend through thepassages 65 to the access ports 63. The intakes 34 may include, but isnot limited thereto, the following: perforated holes, seams, covers,plugs, lids, punch outs, doors, windows, slits, gaskets, diaphragms,valves, or other intake/access mechanisms.

The cover 31 could serve as personal protection glove. The cover 31 maybe a variety of materials such as plastics, polymers, rubber, latex,metal, or any desired material. The cover 31 may include, but notlimited thereto, the following: sheath, casing, well, case, shell,envelope, sleeve, or glove. Moreover, besides protecting the target orpatient, the cover 31 may be used to protect the rest of the device fromdamage or dirt from the target or environment.

Still referring to FIGS. 5A-5B, there is schematically illustrated anadhesive device 33 or adhesive devices that may be disposed, for exampleon the top 6 (shown in FIG. 5A) or alternatively on the cover 33 (shownin FIG. 5B) or both to hold the system 10 in place during treatment andpre or post treatment. Optionally, the adhesive device 33 could bedisposed on other areas of the housing 2 or system 10. The adhesivedevice 33 may include, but not limited thereto, the following: glue,adhesive, VELCRO, tape, mirco-machined spikes, catch, latch or otherholding mechanisms. In addition the adhesive device 33 may beincorporated entirely within the cover 31 to form an integratedcover/adhesive device.

Next, turning to FIG. 6, FIG. 6 schematically illustrates a topperspective view of the hand held ultrasonic imaging system of thepresent invention having a retaining device 32 or retaining devices thatmay disposed, for example on side 13 and/or side 15 (or optionally couldbe disposed on other areas of the housing 2 or system 10). The retainingdevice 32 may include, but not limited thereto, the following: strap,belt, latch, clamp, coupling, joint, keeper, connection, VELCRO, tape,or other retaining mechanisms or structures.

An advantage of the present invention ultrasonic imaging system is thatit may be compact and light weight. For example, the hand held imagingsystem shown in FIGS. 2A-2B, 3A-3C, 4, 5A-5B, and 6, can have a varietyof sizes. In one instance it may have a housing 2 with the dimensions(height, length and width) in inches of about 1×2×2, respectively. Inanother instance, the dimensions (height, length and width) in inchesmay be about 2×6×4, respectively. Of course one should appreciate thatthe housing size may be larger or smaller. Moreover, the hand heldsystem 10 may be lightweight weighing less than about 2 pounds. Ofcourse one should appreciate that it may be heavier or lighter.

The present invention hand held system may be curved so as to fit theshape of the target or a partial area of the target, such as a patientor inanimate object. For example, FIGS. 8A-8B, show a schematiclongitudinal perspective view and lateral side view, respectively, ofthe hand held ultrasonic system 10 wherein the curve of the display 20,housing 2, and/or transducer array 60 is in the longitudinal direction(any select one of these components or combination thereof, as well asother system components may be curved). Some components Whereas, FIGS.9A-9B, show a schematic longitudinal perspective view and lateral sideview, respectively, of the hand held ultrasonic system 10 wherein thecurve of the display 20, housing 2, and/or transducer array 60 is in thelateral direction (any select one of these components or combinationthereof, as well as other system components may be curved). One shouldappreciate that the longitudinal and lateral curves may be combined toform various shapes and contours.

In an embodiment, the present invention ultrasound system and methodproves particularly valuable for continuous monitoring of obstructivesleep apnea. Sleep apnea (obstruction of the air passage in the throat)is highly prevalent, affecting more than eighteen million Americans.Amongst the variants of sleep apnea, obstructive sleep apnea is by farthe most common. It is difficult and expensive to diagnose andrepresents a significant risk to the patient. Typical diagnostic methodsrequire an overnight hospital stay in an instrumented laboratory. Manyat risk patients refuse this inconvenient testing regime and thus goundiagnosed. The present invention low cost sonic window can be coupledwith relatively simple image processing to directly diagnose obstructivesleep apnea in a minimally obtrusive manner. Such an approach could beused in both initial diagnosis and as a warning device in chronic cases.

In an embodiment, the present invention ultrasound system and methodproves particularly valuable as an adjunct to palpation. Manualpalpation is an exceedingly common diagnostic procedure. Clinicians usetheir sense of touch to feel for subcutaneous lumps or even to estimatethe size of lymph nodes or other masses. While palpation undoubtedlyyields valuable qualitative information, numerous studies have shown itto have extremely poor sensitivity and that quantitative size estimatesare completely unreliable. The present invention sonic window wouldoffer a new method and system of observing subcutaneous tissues. It canbe appreciated that various applications can be utilized, includingproviding more reliable and quantitative information than simple manualpalpation.

In an embodiment, the present invention ultrasound system and methodproves particularly valuable for non-destructive evaluation. In a broadvariety of industrial applications ultrasound is used to search forinternal defects in metallic or ceramic parts. Current systems are costeffective, but are unwieldy and acquire limited data, making itdifficult to ensure that a thorough search has been performed. Thepresent invention sonic window allows for more rapid and thoroughexamination than current techniques, and at a competitive cost.

EXAMPLES

The following example is intended for illustrative purposes only and isnot intended to be limiting in any manner.

Example No. 1

Referring to FIG. 7, a schematic block diagram of an embodiment of theinvention is shown, whereby a two-dimensional piezoelectric transducerarray 60 is utilized. The transducer array 60 consists of a 32×32element array of 500×500 um elements 62. These elements can beconstructed by using a commercially available wafer dicing saw to cut aLead Zirconate Titanate (PZT) ceramic that had been mounted to a printedcircuit board. While the printed circuit board does not provide optimalacoustic properties, it can be easily fabricated at a low cost.Selection of non-standard materials as the substrate for the printedcircuit board (such as a thermoplastic) will enable some control overthe acoustic response of the transducer. The printed circuit boardprovides the connection to one side of the elements 62. The other sideof the elements is tied to a common ground plane by adhering a foillayer to the surface using an electrically conductive epoxy.

A transmit-receive switch 70 would be connected directly to thetransducer elements. This switch acts 70 to ensure that either transmitor receive circuitry 75 is connected to the transducer elements 62, butnever both simultaneously. This is essential since the high transmitvoltages (on the order of about 50-200 Volts) would damage the sensitiveamplifiers used in echo reception. Furthermore, the preferred embodimentutilizes a CMOS integrated circuit. Such CMOS processes are relativelyeasily damaged by the application of high voltage.

In one embodiment of this invention the transmit-receive switch andtransmit circuitry are integrated in such a manner as to reduce cost andcomplexity.

A preferred embodiment maintains low cost and system performance byintegrating the preamplifiers 71, amplifiers 72, A/D converters 73,buffer RAM 74, and beamformer 40 into a single CMOS integrated circuit.A single integrated circuit could include a large number of channels,that is, all the circuitry required for reception and focusing of somelarge number of elements. A preferred embodiment would include all thesecircuit components for all 1024 elements on a single integrated circuit.

The preamplifiers 71 provide electrical impedance matching between thetransducer elements 62 and the receiving electronics. They also providesome small amount of fixed gain. The amplifier stage provides a moresignificant level of gain that is adjustable to account for signallosses due to frequency dependant attenuation. The analog to digitalconverters (A/D converters) 73 digitize the received echoes at 8 bitsand a nominal sampling frequency of 40 MHz. Sampled data is then storedtemporarily in the buffer RAM 74. Sampled data is read from this bufferRAM by the beamformer 40. The beamformer delays the echo signalsdifferentially to focus the signals on the location of interest. Thesedelays may have a smaller interval than the sampling interval byemploying digital interpolation filters. Once the echo signals have beenappropriately delayed they may be summed together to yield the focusedsignal for a single line through the tissue. One skilled in the artwould appreciate that the aforementioned focal delays might be updatedat rapid intervals to perform what is commonly known as “dynamicfocusing.”

Focused echo data coming out of the beamformer would be processedfurther by a general purpose digital signal processor (DSP) 41 such asthe Texas Instruments TMS320C55 DSP processor. This DSP 41 processes thefocused line data by performing envelope detection and mapping theenvelope detected data to the appropriate location in the image display.Finally, the image data would be displayed using an LCD screen 20 suchas those employed in handheld televisions, personal digital assistants,or laptop computers.

Transmit timing, focal parameters, image depth, image gain, and otherparameters could be determined by a system control unit 80. This controlunit 80 could consist of a second DSP chip like the one described above.This chip would read user controls and update system settings toimplement user adjustments. This control unit might also employ aninterface to an external storage device and an interface to an externalprinter.

The following U.S. Patents are hereby incorporated by reference hereinin their entirety:

U.S. Pat. No. 4,240,295 to Uranishi, entitled “Ultrasonic DiagnosingApparatus;”

U.S. Pat. No. 5,065,740 to Itoh, entitled “Ultrasonic Medical TreatmentApparatus;”

U.S. Pat. No. 5,097,709 to Masuzawa et al., entitled “Ultrasonic ImagingSystem;”

U.S. Pat. No. 5,722,412 to Pflugrath et al., entitled “Hand HeldUltrasonic Diagnostic Instrument;”

U.S. Pat. No. 5,879,303 to Averkiou et al., entitled “UltrasonicDiagnostic Imaging of Response Frequency Differing from TransmitFrequency;”

U.S. Pat. No. 5,833,613 to Averkiou et al., entitled “UltrasonicDiagnostic Imaging with Contrast Agents;”

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U.S. Pat. No. 6,488,625 to Randall et al., entitled “Medical DiagnosticUltrasound System and Method;”

U.S. Pat. No. 6,497,661 to Brock-Fisher, entitled “Portable UltrasoundDiagnostic Device with Automatic Data Transmission.”

In conclusion, in view of the foregoing, an advantage of the presentinvention ultrasonic imaging system and method provides is ease of use,whereby acquiring and displaying data in the intuitive C-Mode formatlittle or no training will be necessary for clinicians to make use ofthe device.

Another advantage of the present invention ultrasonic imaging system andmethod is low cost, whereby large scale integration of the beamformerwill enable the system to be produced at a very low cost. This will opennumerous applications for which ultrasound was previously costprohibitive.

Still yet, another advantage of the present invention ultrasonic imagingsystem and method is portability, whereby the small size of the systemwill make it easy to carry in a pocket or on a belt attachment. Thiswill make the system or device as available as a stethoscope and willthus open new applications.

Further, another advantage of the present invention ultrasonic imagingsystem and method is that there are no low cost, portable systems thatproduce C-Mode displays.

Moreover, another advantage of the present invention is that it can bebattery operated without a power cord or the like.

Finally, another advantage of the present invention is that entanglementof transducer cable is avoided.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential characteristics thereof. Theforegoing embodiments are therefore to be considered in all respectsillustrative rather than limiting of the invention described herein.Scope of the invention is thus indicated by the appended claims ratherthan by the foregoing description, and all changes which come within themeaning and range of equivalency of the claims are therefore intended tobe embraced herein.

1. (canceled)
 2. An ultrasonic imaging system for producing images of atarget, the system comprising: a housing; a two-dimensional transducerarray disposed on the housing; a display unit disposed on the housing,the display unit defining a planar region, wherein the transducer arrayand the display unit are integrated with the housing, wherein thedisplay unit is configured to display a three-dimensional image; abeamformer disposed within the housing, the beamformer in communicationwith the two-dimensional transducer array, and configured to generatefocused echo data obtained from adjacent planes parallel to a surface ofthe transducer array; and an image processor disposed within thehousing, the image processor configured to: receive focused echo dataobtained from the adjacent planes; and generate a three-dimensionalimage of an image region located below the plane of the display, thethree-dimensional image generated using adjacent image planes located atdifferent depths, and using envelope-detected images from the adjacentplanes combined to yield the three-dimensional image.
 3. The system ofclaim 2, further comprising a control to select the depth of thethree-dimensional image region.
 4. The system of claim 2, wherein theimage processor is configured to generate a three-dimensional image fordisplay on the display unit scaled so that dimensions of thethree-dimensional image presented to the user include actual dimensionsof the target as would be perceived from the perspective of the user ifthe target were visible to the user.
 5. The system of claim 2, whereinthe image processor is configured to generate a three-dimensional imageincluding estimated blood flow velocities represented by respectivecolors.
 6. The system of claim 2, wherein the display unit is adjustablymounted to the housing to provide an adjustable angle between thedisplay and the housing, and wherein the adjustable angle of the displayunit controls an image region angle.
 7. The system of claim 2, whereinthe image processor is configured to generate a three-dimensional imageto be displayed on the display including an animated series of images.8. The system of claim 2, wherein the image processor is configured togenerate a three-dimensional image based on a dataset obtained byaveraging at least two envelope detected images to provide reducedspeckle.
 9. The system of claim 2, wherein the image processor isconfigured to perform speckle pattern decorrelation over time toidentify tissue or blood motion.
 10. The system of claim 2, wherein thetwo-dimensional transducer array is configured to transmit ultrasonicenergy into a target, and wherein the ultrasonic energy transmitted oneor more focused transmit beams.
 11. The system of claim 2, wherein thetwo-dimensional transducer array is configured to transmit ultrasonicenergy into a target, and the two-dimensional transducer array isconfigured to receive ultrasonic echo signals from the target, thetwo-dimensional transducer array configured to provide and receive codedexcitation to increase an effective signal to noise ratio of receivedecho signals.
 12. The system of claim 2, wherein the image processor isconfigured to form the three-dimensional image using receive-onlyspatial compounding.
 13. The system of claim 2, the image processor isconfigured to form the three-dimensional image using transmit-receivecompounding.
 14. The system of claim 2, wherein the image processor isconfigured to form the three-dimensional image by frequency compounding.15. The system of claim 2, wherein the image processor is configured toform the three dimensional image including using tissue harmonicinformation.
 16. The system of claim 2, wherein at least one of saidhousing, display, and two-dimensional transducer array is curved.
 17. Anultrasonic imaging system for producing images of a target, the systemcomprising: a housing; a two-dimensional transducer array disposed onthe housing; a display unit disposed on the housing, the display unitdefining a planar region, wherein the transducer array and the displayunit are integrated with the housing, wherein the display unit isconfigured to display a three-dimensional image, wherein the displayunit is adjustably mounted to the housing to provide an adjustable anglebetween the display and the housing, and wherein the adjustable angle ofthe display unit controls an image region angle; a beamformer disposedwithin the housing, the beamformer in communication with thetwo-dimensional transducer array, and configured to generate focusedecho data obtained from adjacent planes parallel to a surface of thetransducer array; and an image processor disposed within the housing,the image processor configured to: receive focused echo data obtainedfrom the adjacent planes; and generate a three-dimensional image of animage region located below the plane of the display, thethree-dimensional image generated using adjacent image planes located atdifferent depths, and using envelope-detected images from the adjacentplanes combined to yield the three-dimensional image, and the threedimensional image scaled so that dimensions of the three-dimensionalimage presented to the user include actual dimensions of the target aswould be perceived from the perspective of the user if the target werevisible to the user.
 18. A method of imaging a target to produceultrasonic images comprising: obtaining ultrasonic echo signals from atarget using a two-dimensional transducer array; generating athree-dimensional image via an image processor using the ultrasonic echosignals for presentation on a display unit, wherein echo signals includefocused echo data obtained from adjacent planes parallel to a surface ofthe two-dimensional transducer array, wherein the display unit is inalignment with the two-dimensional transducer, and wherein the displayunit, the three-dimensional image processor and the two-dimensionaltransducer are collocated within a housing; and wherein thethree-dimensional image includes an image region located underneath thetwo-dimensional transducer array and located below the plane of thedisplay, the three-dimensional image generated using adjacent imageplanes located at different depths, and using envelope-detected imagesfrom the adjacent planes combined to yield the three-dimensional image.19. The method of claim 17, wherein the three-dimensional image regionis located at a depth beneath the two-dimensional transducer array,wherein the depth is selectable.
 20. The method of claim 17, wherein thethree-dimensional image is formed by averaging at least two envelopedetected images to provide reduced speckle.
 21. The method of claim 17,wherein the three-dimensional image comprises an animation including aseries of images from image planes having different depths within thetarget.